Field of the Invention
The present invention relates to a pneumatic tire having a serration pattern for improving its sidewall appearance so that observers do not notice molding defects such as a dent or a bulge thereon.
Description of the Related Art
Conventionally, a pneumatic tire comprises a pair of sidewall portions each usually with a serration pattern on its outer surface. The serration pattern comprises a plurality of radially extending ridges of similar cross sectional shape. The ridges are arranged a circumferential direction of the tire in substantially parallel each other. The serration pattern helps to improve sidewall appearance directly or indirectly by offering complicated reflected light so that observers do not notice molding defects such as a dent or a bulge on the sidewall portions. Additionally, the serration pattern helps to improve visibility of other branded trademark provided on the serration pattern such as characters, numerical or figures.
Pneumatic tires with various serration patterns mentioned above are disclosed in Japanese patent application laid-open Nos. 2003-252011 and 2003-320818, for example. These documents disclose a serration pattern which comprises an eccentric-serration region having a plurality of ridges each of which extends from an eccentricity center deviated from a tire axis.
Japanese patent application laid-open No. 2004-17829 also discloses a serration pattern which includes two different types of radially inner and outer ridges.
However, conventional serrations patterns of tires mentioned above had plenty of room for improvement in order to improve sidewall appearance of tires that have a thinner sidewall rubber for weight saving.